CommandRegistry
essential

Associates listener functions with commands in a
context-sensitive way using CSS selectors. You can access a global instance of
this class via atom.commands, and commands registered there will be
presented in the command palette.

The global command registry facilitates a style of event handling known as
event delegation that was popularized by jQuery. Atom commands are expressed
as custom DOM events that can be invoked on the currently focused element via
a key binding or manually via the command palette. Rather than binding
listeners for command events directly to DOM nodes, you instead register
command event listeners globally on atom.commands and constrain them to
specific kinds of elements with CSS selectors.

Command names must follow the namespace:action pattern, where namespace
will typically be the name of your package, and action describes the
behavior of your command. If either part consists of multiple words, these
must be separated by hyphens. E.g. awesome-package:turn-it-up-to-eleven.
All words should be lowercased.

As the event bubbles upward through the DOM, all registered event listeners
with matching selectors are invoked in order of specificity. In the event of a
specificity tie, the most recently registered listener is invoked first. This
mirrors the "cascade" semantics of CSS. Event listeners are invoked in the
context of the current DOM node, meaning this always points at
event.currentTarget. As is normally the case with DOM events,
stopPropagation and stopImmediatePropagation can be used to terminate the
bubbling process and prevent invocation of additional listeners.

Example

Here is a command that inserts the current date in an editor:

atom.commands.add 'atom-text-editor',

'user:insert-date':(event)->

editor =@getModel()

editor.insertText(newDate().toLocaleString())

Methods

Registering One Command

add(target, commandName, callback)

Argument

Description

target

A String containing a CSS selector or a DOM element. If you pass a selector, the command will be globally associated with all matching elements. The , combinator is not currently supported. If you pass a DOM element, the command will be associated with just that element.

commandName

A String containing the name of a command you want to handle such as user:insert-date.

callback(event)

A Function to call when the given command is invoked on an element matching the selector. It will be called with this referencing the matching DOM node.

Registering Multiple Commands

add(target, commands)

Argument

Description

target

A String containing a CSS selector or a DOM element. If you pass a selector, the commands will be globally associated with all matching elements. The , combinator is not currently supported. If you pass a DOM element, the command will be associated with just that element.

commands

An Object mapping command names like user:insert-date to listener Functions.

Return values

Returns a Disposable on which .dispose() can be called to remove the
added command handler(s).

This can be useful for testing when you want to simulate the invocation of a
command on a detached DOM node. Otherwise, the DOM node in question needs to
be attached to the document so the event bubbles up to the root node to be
processed.